1. Field of the Invention
The present invention relates to a marking system and a marking method for performing the marking of marking targets such as defects on a subject material, and to a marking apparatus used in this marking system and marking method, and particularly to a marking system, a marking method, and a marking apparatus that enable marking to be performed either directly on or in the vicinity of a marking target.
2. Description of the Related Art
Conventionally, a marking system is known in which defects such as coating unevenness, scratches, and blemishes on the surface of a subject material such as plastic film, paper, and metal plate are detected, and marks showing the positions of the defects are made at the edges of the subject material. An example of this marking system is shown in FIG. 8. The marking system in FIG. 8 is formed by a detector 6, a labeling apparatus 32, and a control apparatus 33. The detector 6 is provided with a light source (not shown) that irradiates light onto a belt shaped subject material 2 that moves in a fixed direction, a camera 3 that captures transmission light or reflection light from the subject material 2 as image signals, and an image processing apparatus 5 that performs image processing on image signals by detecting a defect 4 on the subject material 2 and acquiring the position of the defect 4 on the subject material 2. The labeling apparatus 32 is installed downstream from the detector 6 and affixes a label 31 on an edge of the subject material 2. The control apparatus 33 sends an instruction to affix a label to the labeling apparatus 32 when the defect 4 arrives at the label affixing position of the labeling apparatus 32.
The detection of defects in this marking system is performed in the following manner.
Image signals of the surface of the subject material 2 captured by the camera 3 undergo image processing by the image processing apparatus 5. As a result of the image processing, if a detect 4 is detected on the subject material 2, the position X of the defect 4 in the transverse direction and the position Y of the defect 4 in the movement direction (corresponding to the distance from the front of the subject material) on the subject material 2 are acquired. Here, the position Y in the movement direction of the defect 4 represents a value (referred to below as a count value) obtained by counting, from the front of the subject material, standard pulses emitted from carrier lines (not shown) of the subject material 2 each time the subject material 2 moves a fixed distance. When necessary, the position of the defect 4 may be map displayed on a monitor (not shown), or may be recorded in a recording device (not shown), or it may be printed on paper.
When the position Y of the defect 4 in the movement direction reaches the label affixing position of the labeling apparatus 32, an instruction to affix a label is sent from the control apparatus 33 to the labeling apparatus 32. Here, it is determined that the position Y of the defect 4 in the movement direction has arrived at the label affixing position of the labeling apparatus 32 when the count value of the standard pulses matches a value equal to the sum of the count value representing the position Y of the defect 4 in the movement direction and a count correction value that corresponds to the distance between the camera 3 and the label affixing position, namely, when the count value after the position Y of the defect 4 in the movement direction is detected (i.e., the distance moved from the camera 3) matches the count correction value (i.e., the distance between the camera 3 and the label affixing position).
When the labeling apparatus 32 receives an instruction to affix a label, it affixes a label 31 showing only the position in the movement direction of the defect 4 to the edge of the subject material 2.
When the subject material 2 being examined for defects is a roll of a sheet shaped material such as an antireflection film for a liquid crystal display, CRT, or plasma display or the like, then, as is shown in FIG. 9, the antireflection processing is implemented by coating processing and sheets 34 that match the size of the display are cut out from the belt shaped subject material 2 being examined for defects.
However, when a label is simply affixed to the edge of the subject material 2, the problem arises that it is not possible to ascertain which of the plurality of cut out sheets 34 contains the defect 4.
As a result, in order to remove the sheet 34 containing the defect 4, it has hitherto been necessary to cut out and remove the entire width of the roll at the portion where the label is affixed with the sheets still in the roll state before they are die cut. If the removal is performed after the roll has been die cut, it is necessary either to remove a plurality of sheets 34 adjacent to where the label 31 is attached at the instant they are die cut from the subject material 2 in the form of a roll, or to visually reexamine all of the plurality of sheets 34 die cut from the subject material 2 in the form of a roll. Thus, because either the sheets 34 are cut out and removed in the form of a roll, or else a large number of good sheets are removed together with the defect sheet containing the defect 4 when a plurality of sheets 34 adjacent to where the label 31 is affixed are removed, the problem arises that the yield is reduced and the production efficiency of the die cutting operation is reduced. Moreover, if all of the die cut sheets 34 are visually reexamined, the problem arises that time and labor costs increase. In addition, if a defect is not visually obvious, the concern exists that it may be overlooked in a visual inspection.
It is therefore an aim of the present invention to provide a marking system, a marking method, and a marking apparatus used in this system and method that enable the position of a marking target to be accurately shown, and that reliably enable only that portion containing the marking target to be removed.
The marking system of the present invention comprises: a detector that detects a marking target on a belt shaped subject material moving in a fixed direction at a fixed speed and acquires the position of the marking target on the subject material; a marking apparatus having a head that is located downstream from the detector and that is capable of marking an optional position in a transverse direction of the subject material; and a control apparatus that transmits the position of the marking target in the transverse direction that was acquired by the detector to the marking apparatus, and sends a marking instruction to the marking apparatus when the position of the marking target matches the position of the head of the marking apparatus.
In the marking system of the present invention, it is possible to make a mark either directly on or adjacent to a marking target. Because it is possible according to this marking system to accurately show the position of a marking target, after the subject matter is examined, the reliable removal of only that portion where the marking target is located can be performed.
Moreover, in the marking system of the present invention, if the marking apparatus has a plurality of heads and the control apparatus is able to allocate a head for each marking target, then it is possible for marking failures to be kept to the absolute minimum even when a plurality of marking targets are detected in a short period of time.
The marking method of the present invention is a method in which a mark is made on a marking target on a subject material by a marking apparatus having a head that is capable of marking an optional position in a transverse direction of the subject material. This method comprises: a step in which a marking target on a belt shaped subject material moving in a fixed direction at a fixed speed is detected at a position upstream from the marking apparatus, and the position of the marking target on the subject material is acquired; a step in which the acquired position in the transverse direction of the marking target is transmitted to the marking apparatus; and a step in which a marking instruction is sent to the marking apparatus when the position of the marking target matches the position of the head of the marking apparatus.
In the marking method of the present invention, a mark can be made either directly on or adjacent to a marking target. Because it is possible according to this marking system to accurately show the position of a marking target, after the subject matter is examined, the reliable removal of only that portion where the marking target is located can be performed.
Moreover, in the marking method of the present invention, if the marking apparatus has a plurality of heads and there is included a step in which a head is allocated for each marking target, then it is possible for marking failures to be kept to the absolute minimum even when a plurality of marking targets are detected in a short period of time.
The marking apparatus of the present invention comprises a head for discharging ink and a box for housing the head. The head is capable of movement inside the box, and an outlet for ink discharged from the head and an air outlet are provided in the box.
In the marking apparatus of the present invention, it is possible to prevent dust generated by the movement of a head from falling onto the subject material.
In addition, if the marking apparatus of the present invention has a plurality of heads, it is possible for marking failures to be kept to the absolute minimum even when a plurality of marking targets are detected in a short period of time.
Moreover, by connecting an ink cartridge to the head, no hose is needed to connect the head to the inkjet printer body, enabling the space required to be reduced and the movement of the head to be speeded up. In addition, problems connected with blockages of the hose can be avoided.